Process of making a cellulose acetate soluble in ethyl acetate.



TED s-TAfrns oniuon. 1

FRIEIH'tICH COLIJI SOHO NN, OF FRANKFOE'I-GN DHE-MAIN, AND FRIEDRICH RUPPERT, OF MAINZ-MOMBACH, GERMANY, ASSIGNORS T VEREIN FIIR CHEMISCHE INDUS- TRIE IN MAINZ, OF MAINZ, GERMANY.

I PROCESS OF MAKING- A CELLULOSE ACETATE SOLUBLE IN ETHYL ACETATE.

No Drawing.

Patented Sept. 1, 1914.

Application filed February 18,1913. Serial No. 749,235.

To all whom-it-may concern:

' Be it known that we, FRIEDRICH- CoLLI- scHoNN, doctor of philosophy and chemist, asubject of the King of Prussia-,and resident of Fra'nkfort-on-the-Main, Germany,

and F RIEDRIoH RUPPERT, doctor of philosophy and chemist, a subject of the King of ,acetyl cellulose soluble in chloroform and: 'acetyl cellulose soluble in acetone. o have now found a cellulose acetate,

which has very valuable technical properties and is distinguished from the hitherto known cellulose acetate by its property to dissolve in pure ethyl acetate to clear, very viscous solutions.

The process for the manufacture of the said new cellulose acetate consists in heating the cellulose acetates soluble in chloroform or acetone, in a solution containing water, in absence of any'suhstance having a. hydrolytic action, as for instance inorganic acids, acid salts, at a temperature of 90 to 110 0., till a sample precipitated by water and dried dissolves in pure ethyl acetate to a clear solution. For an accurate carrying out of this transformation it is essential that the cellulose acetate remains dissolved for the whole duration of the operation. In

practising this process, we can start either from dry cellulose acetates or directly from the reaction mass resulting from the known .acetylating processes, without intermediate separation of the cellulose acetate. In thislatter case care must be taken to-render the contact substance contained in'the reaction mass nnocuous by admixing convenient add1t1o-ns to this latter.

The invention is illustrated by the followmg examples:

Example I: 50 parts of cellulose acetate soluble in chloroform are dissolved at 100 C. 1n 509 parts of acetic acid of 95 per cent. andvhea'ted at 100 C. till a sample of the mass dissolves in ethyl acetate to a clear and viscous solution, what occurs generally after about 20 hours.

Example II: The operation is conducted as in Example I with the difi'erence that acetic acid of 90 per cent. is employed and the temperature is raised to 105110 C.

Example III: 50 parts of cellulose acetate are heated together with400 acid of 90 per cent. at 100 110 C. till a sample dissolves completely in ethyl acetate ether, what occurs generally after 3-5 hours.

Example IV: To the reaction mass obtained for instance according to theprocess of German Patent No. 159524 by acting cautiously'with 800 parts of acetic anhydrid, 600 parts of glacial acetic acid and 5 parts of sulfuric acid on 200 parts of cotton,

parts of formic I are added the quantity of acetic acid of 50 per cent. necessary to the transformation into acetic acid of per cent, that is to say about 285 parts of acetic acid of 50 per cent, and 10 parts of sodium acetate free of water and the so obtained mixture is heated to 110 C. till a sample dissolves 'in ethyl acetate to a clear solution.

Example V: The-reaction mass obtained by the action of 350 parts of. acetic anhydrid and 400 parts of glacial acetic acid onlOO parts of cellulose, in presence of 5; parts of zinc chlorid and 1 part of hydrochloric acid, is mixed with parts of acetic acid of 50 per cent. previously mixed with 12 parts of I an. aqueous ammonia solution of 20per'cent.

till a sample dissolves in ethyl acetate to a clear solution.

From the known cellulose acetates, soluble in ethyl acetate, the new cellulose acetate is distinguishedby the particularly great viscosity of its solutions in an ethyl acetate.

What We claim is:

The described process for the manufacture of cellulose acetate soluble ill-ethyl acetate, consisting in heating solutions of the known cellulose acetates, which contain water,-but no substances having a hydrotill a sample of the reaction massdissolves 15 in ethyl acetate to a clear solution.

In witness whereof We have hereunto signed our names this 7th day of February,

1913, in the presence. of two subscribing witnesses.

DR. FRIEDRICH GOLLISCHON-Ng 1 DR. FRIEDRICH BUFFER-T," V

l/Vitnesses: i

' JEAN GRUND,

CARL GRUND 

